I think, therefore I experiment

First, obligatory Existential Comics link. Second, the real trolley problem is obviously why the hell are they calling a train a trolley. Look, this is a train. This is a trolley. Killing one person with a trolley would be extremely difficult, never mind five. And third, we do actually know the answer to this one in real life.

That's the essential stuff out of the way. On to the article, which is about the use of thought experiments in general rather than the "trolley" problem specifically.

While thought experiments are as old as philosophy itself, the weight placed on them in recent philosophy is distinctive. Even when scenarios are highly unrealistic, judgments about them are thought to have wide-ranging implications for what should be done in the real world. The assumption is that, if you can show that a point of ethical principle holds in one artfully designed case, however bizarre, then this tells us something significant. Many non-philosophers baulk at this suggestion. 

Consider ‘The Violinist’, a much-discussed case from Judith Jarvis Thomson’s 1971 defence of abortion:
You wake up in the morning and find yourself back-to-back in bed with an unconscious violinist. He has been found to have a fatal kidney ailment, and the Society of Music Lovers has canvassed all the available medical records and found that you alone have the right blood type to help. They have therefore kidnapped you, and last night the violinist’s circulatory system was plugged into yours, so that your kidneys can be used to extract poisons from his blood as well as your own. The director of the hospital now tells you: ‘Look, we’re sorry the Society of Music Lovers did this to you – we would never have permitted it if we had known. But still, they did it, and the violinist now is plugged into you. To unplug you would be to kill him. But never mind, it’s only for nine months. By then he will have recovered from his ailment, and can safely be unplugged from you.' 

Readers are supposed to judge that the violinist, despite having as much right to life as anyone else, doesn’t thereby have the right to use the body and organs of someone who hasn’t consented to this – even if this is the only way for him to remain alive. This is supposed to imply that, even if it is admitted that the foetus has a right to life, it doesn’t yet follow that it has a right to the means to survive where that involves the use of an unconsenting other’s body.

Wow. That's insane. Now, I'm a big fan of indirect analogies - they encourage thinking carefully about a situation, whereas direct analogies are largely pointless. But this is so indirect as to be utterly irrelevant. I don't even know where to begin with the moral differences between the situations intended for comparison here, so I won't try.

What I've always liked about the Trolley Train Problem is its attempt to reduce things to the core issue : is it better to kill one person than five, given no other knowledge of the situation ? Obviously the answer to that is yes, it is. But as soon as you introduce even anything else at all, complications spiral. Why can't I stop the train ? How the hell is pushing a fat guy off a bridge going to help ? (Seriously, FFS on that one, what were they thinking drinking ?) Those aspects make the whole thing feel distinctly uncomfortable, in a different way to the moral question itself :

In the few instances I tried to use this thought experiment in teaching ethics to clinicians, they mostly found it a bad and confusing example. Their problem is that they know too much. For them, the example is physiologically and institutionally implausible, and problematically vague in relevant details of what happened and how. (Why does the Society of Music Lovers have access to confidential medical records? Is the operation supposed to have taken place in hospital, or do they have their own private operating facility?) Moreover, clinicians find this thought experiment bizarre in its complete lack of attention to other plausible real-world alternatives, such as dialysis or transplant. As a result, excellent clinicians might fail to even see the analogy with pregnancy, let alone find it helpful in their ethical reasoning about abortion.

What's never really occurred to me is the root issue of what makes the more complicated situation feel different, which the article does an excellent job of putting its finger on : the nuances of the situation matter because they change the ethical problem. Say there was some way of stopping the train instead of diverting it but with some risk - that's a different moral question. Someone having to endure being tied to a violinist experiences different moral questions to one wrestling with abortion. The detailed aspects to each situation allow for different options, and ignoring those is unavoidably immoral. Fundamentally, sometimes you can't reduce it to a simple case. The details are essential and cannot be separated from the moral issue at hand. So the question, "is it better to kill one person than five ?" may have literally no context-independent meaning at all - it would be better in some situations but not in others. The key for addressing a moral dilemma by analogy is to a construct a relevant analogy in which the answer already seems clearer.

Faced with people who don’t ‘get’ a thought experiment, the temptation for philosophers is to say that these people aren’t sufficiently good at isolating what is ethically relevant. Obviously, such a response risks being self-serving, and tends to gloss over an important question: how should we determine what are the ethically relevant features of a situation? Why, for example, should a philosopher sitting in an armchair be in a better position to determine the ethically relevant features of ‘The Violinist’ than someone who’s worked with thousands of patients?

 All this makes reasoning about thought experiments strikingly unlike good ethical reasoning about real-life cases. In real life, the skill and creativity in ethical thinking about complex cases are in finding the right way of framing the problem. Imaginative ethical thinkers look beyond the small menu of obvious options to uncover novel approaches that better allow competing values to be reconciled. The more contextual knowledge and experience a thinker has, the more they have to draw on in coming to a wise decision.

The greater one’s contextual expertise, the more likely one is to suffer the problem of ‘too much knowledge’ when faced with thought experiments stipulating facts and circumstances that make little sense given one’s domain-specific experience. So, while philosophers tend to assume that they make ethical choices clearer and more rigorous by moving them on to abstract and context-free territory, such gains are likely to be experienced as losses in clarity by those with relevant situational expertise.

Clearly thought experiments do have value. By attacking the problem in different ways, they help us identify the similarities and differences, looking for what's extraneous (the colour of the train, say) and what's really important (who the people are). In this way we try and seek out the appropriate principle on which to act. Quite often I find myself profoundly disagreeing with the conclusion the author intended, and it's in those disagreements it becomes possible to learn something.

The Aeon piece then goes into a lengthy discussion about whether thought experiments are literally experiments or merely appeals to the imagination. It's decent enough, but to be honest I'm not really sure what the point of it is : it seems clear that they're not literally experiments but "intuition pumps", as the author calls it, for getting to the heart of the matter. This is not at all easy. Clearly it's very difficult to illuminate the underlying ethical principles, but that there are many unique and complicating factors to every situation doesn't mean that underlying principles don't exist. We just have to keep examining and revising in accordance with new evidence. Much like science, really... which means we've come full circle and thought experiments are experiments after all. Whoops.

What is the problem with ethical trolley problems? - James Wilson | Aeon Essays

Much recent work in analytic philosophy pins its hopes on learning from imaginary cases. Starting from seminal contributions by philosophers such as Robert Nozick and Derek Parfit, this work champions the use of thought experiments - short hypothetical scenarios designed to probe or persuade on a point of ethical principle.